expression, noun
conscientious vote; unsullied vote
A set phrase often used in political contexts to describe a vote cast with integrity, free from corruption or undue influence. The classical adjective 清き (clear, pure) modifies 一票 (one vote).
選挙では、清き一票を投じてください。
Please cast your conscientious vote in the election.
彼は清き一票の大切さを訴えた。
He stressed the importance of an unsullied vote.